The following are confirmed and canon:

Kanto:
- Protagonist is Red
- He picks Charmander
>Source: GSC, HGSS, Origins, Generations (ep. 3)

Johto:
- Protagonist is Ethan
>Source: Generations (ep. 4)

Hoenn:
- Protagonist is Brendan
>Source: ORAS AT, Generations (ep. 7)

Sinnoh:
- Nothing is confirmed

Unova:
- BW protagonist is unconfirmed
- B2W2 protagonist is Nate
- Nate's starter is Oshawott
- Rosa's starter is Snivy
>Source: B2W2 AT

Kalos:
- Nothing is confirmed

Okay?